Gripping devices in the form of automated hands are known in the fields of prosthetics and robotics.
Many automated hands comprise a ‘palm’ and a plurality of gripping members or ‘fingers’. The fingers of the hand are adapted to move so that objects can be gripped between the fingers.
United States patent publication no. US 2010/0259057 discloses a robotic hand with human-like fingers that are able to curl and flex using a series of pulleys and cables. United States patent application publication no. US 2011/0144770 discloses an automated finger mechanism for an automated hand. The fingers are able to curl and flex using differential linkages. However, in both forms of automated hand, the palm of the hand is fixed and does not comprise moveable portions and the fingers are not able to move laterally. This makes it very difficult for the hand to effectively and safely grip an object.
United States patent publication no. US 2010/0176615 discloses a multi-fingered robotic hand comprising a plurality of gripping members in the form of fingers and a thumb. Each of the fingers and thumb comprise hinged joints to allow the fingers and thumb to curl and flex. The robotic hand described has a palm comprising at least two palm portions attached together along an elongate hinged joint. The fingers and thumb extend from the palm of the hand in the direction of the y-axis. Metacarpal hinged joints between the fingers and the palm of the hand imitate the metacarpal joints of a human hand. The metacarpal hinged joints lie along the x-axis, which is perpendicular to the longitudinal direction of the fingers. These metacarpal hinged joints allow the fingers to pivot about the x-axis in a similar way as metacarpal joints allow human fingers to move relative to the palm of the human hand.
The elongate hinged joint connecting the two palm portions together is located along a second axis that is parallel to the x-axis of the metacarpal hinged joints of the fingers. The elongate hinged joint allows a first palm portion to move relative to a second palm portion so that the connection angle between the two palm portions can be varied to provide a compliant palm. The compliant palm therefore acts as an extension of the fingers by allowing the fingers and palm of the hand to curl and flex in the same way. However, the palm of the hand is unable to move about an axis that lies parallel to the y-axis or, in other words, neither the fingers of the hand nor the palm of the hand allow for lateral movement. Therefore, the palm of the hand can bend around an object in one direction only.
Contrast this with the human fingers, thumb, and palm, in which the metacarpal bones can move independently to some extent to bring the sides of the palm toward each other and in which the fingers and thumb can also move sideways to some extent. This movement, together with the curling and flexing abilities of the fingers and thumb allows the hand to grip an object very effectively, particularly a rounded or curved object, which can be ‘cupped’ by the hand.
Another drawback of known automated hands is that the fingers of the hand are particularly vulnerable to impacts from lateral forces. Furthermore, known automated hands typically appear bulky and look and feel unnatural.
It is an object of the invention to provide an automated hand comprising a compliant palm that goes at least some way towards overcoming or ameliorating one or more disadvantages of the prior art or that at least provides the public with a useful alternative.